Investigation On Performance Of Perovskite Solar Cells Based On ZnO Electronic Transport Materials

Perovskite solar cells,which have the advantages of high photoelectric conversion efficiency,simple preparation process and low cost,have developed rapidly in recent years,and the highest photoelectric conversion efficiency has reached 22.7%.In classical perovskite solar cells,TiO2 is often used as the electron transport layer.The energy levels of ZnO semiconductor materials are close to TiO2,and have higher electron mobility than TiO2,the synthesis temperature is also relatively lower,crystal structures can controlled easier and have more synthetic methods.These advantages attract more and more scholars to pay attention to it.In this paper,perovskite absorption layer was prepared by using CH3NH3PbI3 as raw material,and nano structure ZnO as electron transport layer.spiro-OMeTAD as hole transport layer,made of metal electrode by magnetron sputtering plating,simple structure formation of FTO/ZnO/CH3NH3Pbl3/spiro-OMeTAD/Ag.In this paper,the effect of preparation process of nanostructured ZnO and CH3NH3Pbl3 on film forming quality and performance of ZnO perovskite solar cell is studied.The optimization direction and strategy of ZnO type perovskite solar cell are put forward.The main contents of the study are as follows:1.LEffects of nanostructures ZnO on the performance of the PSCsThe effect of preparation process of nanostructured ZnO on the performance of the battery was studied.The results show that the suitable thickness and annealing temperature of nanostructured ZnO thin films can reduce carrier recombination,bypass current and transmission resistance.With the increase of spin-coating times,the ability of blocking holes in nanostructured ZnO layer increases,but the resistance of electron transmission also increases,which makes the short-circuit current maximum at a certain number of spin-coating times,and then decreases.With the increase of annealing temperature,the crystalline quality of nanostructured ZnO thin films becomes better and better,which makes the surface defects of the films decrease and beneficial to reduce the transfer resistance and charge recombination.However,high annealing temperature leads to nanostructured ZnO grain gap increase,and the performance of the cell can not be improved.It can be concluded that there is a maximum annealing temperature for the ZnO based perovskite solar cells to obtain the optimal performance.The experimental results show that when the film thickness is 1400 nm(spin-coating 4 times,annealing temperature is 100℃),the performance of the battery device is the best.The battery performance are Jsc=12.85 mA/cm2,Voc=0.97 V,FF = 0.49,PCE = 6.11%.2.Effects of preparation conditions of CH3NH3PbI3 film on the performance of the PSCsThe effects of spin coating speed of PbI2 and annealing temperature of perovskite on the performance of perovskite battery were studied.The experimental results show that the rotation speed of PbI2 spins has a significant effect on the compactness and grain size of perovskite films.When PbI2 was spin-coated at a minimum rotational speed of 1000 rpm,the DMF-DMSO solution of PbI2 was deposited in the ZnO electron transport layer with less centrifugal force,which affected the smoothness of perovskite film surface.When PbI2 spin-coating speed up to 2500 rpm,the centrifugal force of the solution is larger,most of the Pbl2-DMF-DMSO solution throw out led to PbI2 film thinner,the amount of CH3NH3PbI3 formed after the reaction with CH3NH3I is decrease,the formed film has more pinholes,and the film is not compact enough.Therefore,it is important for the battery to obtain better Jsc and PCE with proper PbI2 spin-coating speed,and the appropriate annealing temperature of CH3NH3PbI3 film is beneficial to improve the crystallization quality and solvent volatilization.Higher annealing temperature in a certain range promotes the transport of carriers in the CH3NH3PIbI3 optical absorption layer and reduces the recombination probability of carriers.When the annealing temperature is too low,the residual solvent on the surface of the CH3NH3PbI3 film can not be completely volatilized.The prepared CH3NH3PbI3 thin film has smaller grain size but more surface impurities,and the stability of the battery is poor.When annealing temperature is too high,CH3NH3PIbI3 thin films are decomposed to PbI2 rapidly,and their optical absorption capacity is greatly reduced,which seriously shortens the carrier lifetime,which is unfavorable to the performance of the battery.The first two points in this thesis have the best performance under the condition of Pbl2 solution spin-coating speed of 1500 rpm and annealing temperature of 90℃,the Jsc=11.42mA/cm2,Voc=1.00V,FF=0.52,PCE=5.98%。3.The effect of TiO2 doping concentration on the performance of ZnO PSCsIn this paper,perovskite solar cells were fabricated by doping ZnO thin films with different concentrations of TiO2 and using them as electron transport materials.The experimental results show that the doping of TiO2 can greatly improve the open circuit voltage and energy conversion efficiency.When the concentration of TiO2 is 0.1mol/L,the Jsc =15.64 mA/cm2,Voc=1.13 V,FF=0.56,PCE=9.92%。...